The biochemistry, structure and function of the individual components of the flagellum will be investigated using wild-type Chlamydomonas and mutants having a defective flagellar apparatus. Studies will be carried out to determine what specific ATPases and proteins are contained in the inner and outer arms, the radial spokes and the central sheath, and to more precisely define the roles of each of these components in flagellar movement. Studies will aslo be carried out to determine the molecular composition of the different dyneins of Chlamydomanas, and to determine the functions and locations in the flagellum of the Ca ions ATPase, the adenylate kinase and the nucleoside diphosphokinase. The biochemistry and functions of the nexin and peripheral links will be investigated, and mutants which have abnormal flagellar movement will be analyzed to identify the specific components which control the form and synchrony of the flagellar beat. Studies are also planned to determine the sequence of steps in the formation of the axoneme, and the mechanisms which regulate axonemal assembly and flagellar growth. The sequence of attachment of the extramicrotuvular structures to the flagellar microtubules will be analyzed by studying a. the in vivo restoration of normal movement to paralyzed flagella of non-motile strains following fusion of gametes of these strains with wild-type gametes to form quadriflagellate prozygotes, and b. the in vitro repair and reactivation of isolated axonemes of the mutants following mixing of the defective axonemes with prepararions containing those components lacking in the mutants. In addition, pulse-chase experiments will be carried out to determine the time of synthesis of flagellar proteins, when they are transported into the flagellum, and whether they undergo cleavage or covalent linkage during their assembly into the axonemal superstructure. Finally, mutants having abnormal flagellar development will be investigated to determine what specific factors are invoved in the control of flagellar morphogenesis.